Electric furnace



Sept. 15, 1925.

J. H. GRAY ELECTRIC FURNACE 1920 2 Sheets-Sheet 1 Filed Nov. 13

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lllllllllllln II/VEIIT0R James H Gray Wad, nronmsy Patented Sept; 15,19251 UNITED STATES PATENT OFFICE.

JAMES H. GRAY, OENEW YO'RK, N. Y.

ELECTRIC FURNACE.

Application filed Fovember 13, 1920. Serial No. 423,86 7.

To all whom it may concern:

Be it known that L'JAMES H..GRAY, a

citizen of the United States, and resident of v Figs. 3 and 4 aresections respectively on lines 3-3 and l=4 of Fig. 2;

Fig. 5 is a section on the line 5-5 of Fig. 2;

Fig. 6 is a cross-section of an alternative form of supporting arm.

Referring to the embodiment of the inven tion illustrated the furnace 1has on its bot tom a rocker 2 resting on a curved track 3, the furnacebeing tilted to the position shown in dotted lines by meansof a link 4extending to any suitable gearing. The furnace and tilting mechanismthereof constitute no part of this invention and may be of any usual orsuitable design. The roof 5 of the furnace is pierced for the passage ofthe electrodes 6 through the usual cooling rings 7. Each electrode hasto be adjusted vertically and separately from the others and is equippedwith the holder and adjusting means hereinafter described.

To permit the tilting of the furnace without moving the electrodeslengthwise, the supporting and adjusting mechanism l is mounted on thefurnace and tilted with it. Each electrode is mounted in a clamp 8 whichis connected at its rear end to a horizontal arm or bus, bar 9 which isconnected by means of flexible cables 10 to the transformer or othersource of supply, the cables being of a length sufficient to permit thetilting of the furnace as shown. The center of rotation of the tiltingfurnace is at 11. The cables 10 extend upward from their connection tothe bus bar, or supporting arm. As

"the point of connection, therefore, swings upward as well ashorizontally, during the tilting of the furnace, the amount of take-upon the cables 10, or the amount of slack which has to be allowed inthese cables, is comparatively little. A much shorter connection throughsuch cables is established than where their two ends are in horizontalalignment with each other or nearly so, as

' hasbeen the usual practice heretofore.

For the heavy currents needed in electric arc furnaces, the reactance inthe cables, being proportional to their length, is very considerable. Bythis arrangement I have reducedsuch length and saved the loss of currentby such reactance and also provided an arrangement by which a greaterquantity'of current can be put into the furnace.

I have also arranged the motors and mechanism for adjusting theelectrodes entirely below the cables 10 so as to avoid loss of currentwhich has occurred in previous installations by reason of the inter--ference of the metal in the adjusting mechanism and supports surroundingor passing between such cables.

For this purpose each of the arms 9 which with the brackets 8 form theholders for the electrodes is mounted on a post 12 extending downwardtherefrom along the side of the furnace and this post is elevated andlowered by mechanism also mounted on the side of the furnace below thelevel of the arms 9. On top of each post 12 is a cap 13 on which the armis mounted with insulating material 1 1' interposed .in the joint. Onthe lower end of the post is mounted a pulley 15. Brackets 17 in theform of channels are mounted on the furnace and carry guide channels 18between which are guided sleeves 19 and 20 (Figs. 3' and 5) fastened onthe upper and lower ends of the post 12, the sleeves 19 and 20 beingformed with flanges 21 which fit into the corners of the rectangularguideway formed by the channels 18. Fastened on the outside of thechannels 18, are reinforcing channels 22.

On the inner edges of the guideway near the'top are mounted bearingblocks 23 carrying a guide roller 24 against which bears the inner faceof the guide block 19. On the lower end of the guideway on its outerside is mounted a similar guide roller 25 an I-beam against which bearsthe outer face of the lower guide block 20. These guide rollers 24 and25 are arranged to take the lateral bearing of the post due to theweight of the overhanging armand electrode.

At the upper end of the guideway, on the outer side, are mountedbrackets 26 carrying fixed guide pulleys .27. Cables 28 are attached attheir inner ends to the brackets 17, passed downward over the pulleys 15and up over the fixed pulleys 27 and thence to a winding drum 28 drivenfrom a motor 29 which is mounted on a bracket 30 on the outer face ofthe guideway. When the cable is taken up on the drum it lifts the truckor 0st 12 and with it the arm 9 and electrode 6. hen the furnace istilted all the parts described move together, retaining their relativepositions and preventing longitudinal movement of the electrodes.

Each arm 9-is formed at its rear end with a hollowbracket 31 and thecables 10 are fastened around the outside thereof, as shown inFig. 4. Acooling system is provided for each supporting arm and clamp. The arm isreferably made in the form of FFig. 4) with passages 32 run ninglongitudinally throu h it and leading out near the rear end of the armto the usual or any suitable water connections for supply and discharge,as indicated, for example, at 3 2 and 32", Fig. 2. One of the passa es32 is connected near the forward end of the arm through pipes 33 to theinlet end of a water passage in the clamping arm 8, and the dischargeend of the same passage is connected through a pipe 34 to the oppositepassage 32 of the arm.

In Fig. 6, there is shown an alternative form of supporting arm 9* whichis box shaped with a diaphragm 35 which divides the space within the arminto two passages 36 for the circulating of cooling water.

The arms 9, or 9*, which serve both to support the electrodes and toconvey current thereto may be made in various forms, in tegral or builtup. They may be made of copper for greater conductivity. Or they maymade of steel with copper bars extending along the top of them; thelatter construction being useful particularly where the required currentis so low as not to involve serious losses through reactance.

Though I have described with great particularity in detail a certainembodiment of my invention, yet it is not to be understood therefromthat the invention is restricted to the embodiment disclosed. Variousmodifications thereof may be made by those skilled in the art withoutdeparture from the invention as defined in the following claims.

lVhat I claim is:

1. An electric furnace having electrode holders comprising armsextending across the top of the furnace and carrying the weight of saidelectrodes and also serving as conductors to convey current to saidelectrodes, said arms having passages formed therein to permit thecirculation of a cooling medium in intimate contact therewith.

2. An electric furnace having electrode holders comprising a clamp and asupporting arm therefor, said arm having passages formed therein topermit the circulation of a cooling fluid in intimate contact therewith.

3. An electric furnace having electrode holders comprising arms carryingthe weight of the electrodes and serving as conductors to convey currentto said electrodes and having connected to the rear ends thereofflexible cables extending to a fixed point above said holders so thatcables of minimum length can be used thereby cutting down the reactanceand attendant current losses.

at. An electric furnace having electrode holders comprising armsextending across the top of the furnace, posts extending down from saidarms along the side of the furnace guides on the furnace for said postslocated below the roof of the furnace, motors mounted on the furnace andcables operatively connected with said motors and said posts whereby theelectrodes are raised and lowered.

5. An electric furnace having electrode holders comprising armsextending across the top of the furnace, posts secured below said arms,guiding means for said posts located Wholly below said arms and motorsmounted on the furnace operatively connected with cables engaging thelower ends of said posts and arranged to lift and lower said arms, saidguiding means being so arranged that said arms never project therebetween. i

6. An. electric furnace having electrode holders comprising armsextending across the top of the furnace, posts extending down from saidarms alon the side of the furnace, guides on the furnace for said postsand motors mounted on said furnace and cables connected to said furnaceand to said motors and engaging in their bights the said posts so as tolift and lower the same as the motors are operated.

In witness whereof, I have hereunto signed my name.

JAMES H. GRAY

